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U.S. Department of Energy
Office of Scientific and Technical Information

Methods and apparatus for investigating an earth formation and compensating for borehole environmental effects

Patent ·
OSTI ID:6416106
In the illustrative embodiment of the invention disclosed, a neutron porosity logging tool adapted to log a mud-filled borehole includes one or more pairs of epi-thermal and/or thermal neutron detectors. The detector count rates are corrected to the effective count rates for fresh water in the borehole by applying thereto empirically-derived correction terms that are functionally related to the hydrogen index of the mud and, in the case of thermal detectors, also to the thermal neutron absorption properties in the mud.
Assignee:
Schlumberger Technology Corporation
Patent Number(s):
US 4524274
OSTI ID:
6416106
Country of Publication:
United States
Language:
English